Spermogonia and the so-called Spermatia. 13 
visited this plant. Tulasne* remarked the odour of the 
spermogonia of cidium pini and of Uredo serratula, 
which he compared to that of the pollen of willows. 
Léveillé-+ noticed the odour of &cidium tragopogonis, 
which he said resembled the perfume of some flower. 
Rathay indicates that the possession of the pleasant odours 
is a special characteristic of those Uredines which have a 
perennial mycelium. The plants thus invaded are further 
rendered more conspicuous to insects by the manner in 
which the affected leaves or shoots grow. As he says, these 
have a strong negative geotropism. Not only are they 
more erect, standing above the other leaves or shoots, but 
they are further characterized by an alteration in their 
foliage ; while they are, as a rule, not only paler in colour, 
but also modified in form, being either more attenuated or 
the reverse. The Uredines with a short-lived mycelium, on 
the contrary, have their spermogonia produced upon the 
upper surface of the leaves on brilliantly coloured spots, 
which contrast more or less strikingly with the green colour 
of the healthy foliage. These spots are generally bright 
yellow or orange, often with a tinge of red. Sometimes 
they are white (4c. fabe) or purple-red (4c. rumicis). 
The negative geotropism is not, however, confined to the 
species with the perennial mycelium ; I have noticed it 
very markedly with some leaves of Senecio jacobea, upon 
which I had produced the zcidium of Puccinia scheleriana ; 
as soon as the ecidial spots became sufficiently developed 
to produce spermogonia, the leaves which bore them became 
almost erect, while the unaffected leaves remained horizontal. 
In either case the darker paraphyses surmounting each 
conceptacle finally attract the insect to the sugary globule. 
* Tulasne, ‘2° Mémoire,” p. 118. 
t Léveillé, in D’Orbigny’s ‘‘ Dict. Univ. d’Hist. Nat.,” tome xii. p. 175, 
sub. Uredines, 
